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'1' -- Possible downref: Non-RFC (?) normative reference: ref. '2' Summary: 9 errors (**), 0 flaws (~~), 21 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IETF Fax working group Graham Klyne 3 Request for comments: nnnn 5GM/Content Technologies 4 Category: Work-in-progress Lloyd McIntyre 5 Xerox Corporation 6 8 January 1999 7 Expires: July 1999 9 Content feature schema for Internet fax 10 12 Status of this memo 14 This document is an Internet-Draft. Internet-Drafts are working 15 documents of the Internet Engineering Task Force (IETF), its areas, 16 and its working groups. Note that other groups may also distribute 17 working documents as Internet-Drafts. 19 Internet-Drafts are draft documents valid for a maximum of six 20 months and may be updated, replaced, or obsoleted by other 21 documents at any time. It is inappropriate to use Internet-Drafts 22 as reference material or to cite them other than as ``work in 23 progress''. 25 To view the entire list of current Internet-Drafts, please check 26 the "1id-abstracts.txt" listing contained in the Internet-Drafts 27 Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net 28 (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au 29 (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US 30 West Coast). 32 [[INTENDED STATUS: This document specifies an Internet standards 33 track protocol for the Internet community, and requests discussion 34 and suggestions for improvements. Please refer to the current 35 edition of the "Internet Official Protocol Standards" (STD 1) for 36 the standardization state and status of this protocol. 37 Distribution of this memo is unlimited.]] 39 Copyright Notice 41 Copyright (C) The Internet Society 1998. All Rights Reserved. 43 Abstract 45 This document defines a content feature schema that is a profile of 46 the media feature registration mechanisms [1,2,3] for use in 47 performing capability identification between extended Internet fax 48 systems [5]. 50 RFC nnnn Content feature schema for Internet fax 51 8 January 199 53 This document does not describe any specific mechanisms for 54 communicating capability information, but does presume that any 55 such mechanisms will transfer textual values. It specifies a 56 textual format to be used for describing Internet fax capability 57 information. 59 RFC nnnn Content feature schema for Internet fax 60 8 January 199 62 Table of contents 64 1. Introduction ............................................4 65 1.1 Organization of this document 4 66 1.2 Terminology and document conventions 4 67 2. Fax feature schema syntax ...............................5 68 3. Internet fax feature tags ...............................5 69 3.1 Image size 6 70 3.2 Resolution 6 71 3.3 Media type 7 72 3.4 Paper Size 7 73 3.5 Color capability 8 74 3.6 Color model 9 75 3.7 Image coding 11 76 4. Examples ................................................13 77 4.1 Simple mode Internet fax system 13 78 4.2 High-end black-and-white Internet fax system 14 79 4.3 Grey-scale Internet fax system 14 80 4.4 Full-color Internet fax system 15 81 4.5 Full-color Internet fax system (MRC) 16 82 4.6 Sender and receiver feature matching 16 83 5. IANA considerations .....................................19 84 6. Security considerations .................................19 85 6.1 Capability descriptions and mechanisms 19 86 6.2 Specific threats 19 87 7. Full copyright statement ................................20 88 8. Acknowledgements ........................................20 89 9. References ..............................................20 90 10. Authors' addresses .....................................23 91 Appendix A: Feature registrations ..........................24 92 A.1 Image size 24 93 A.2 Resolution aspect ratio 26 94 A.3 Color levels 28 95 A.4 Color space 30 96 A.5 CIELAB color depth 33 97 A.6 CIELAB color gamut 35 98 A.7 Image file structure 38 99 A.8 Image data coding 40 100 A.9 Image coding constraint 42 101 A.10 JBIG stripe size 44 102 A.11 Image interleave 46 103 A.12 Color subsampling 48 104 A.13 MRC availability and mode 50 105 A.14 MRC maximum stripe size 52 106 Appendix B: TIFF mode descriptions .........................54 107 Appendix C: Revision history ...............................55 109 RFC nnnn Content feature schema for Internet fax 110 8 January 199 112 1. Introduction 114 This document defines a content feature schema that is a profile of 115 the media feature registration mechanisms [1,2,3] for use in 116 performing capability identification between extended Internet fax 117 systems [5]. 119 This document does not describe any specific mechanisms for 120 communicating capability information, but does presume that any 121 such mechanisms will transfer textual values. It specifies a 122 textual format to be used for describing Internet fax capability 123 information. 125 The range of capabilities that can be indicated are based on those 126 covered by the TIFF file format for Internet fax [7] and Group 3 127 facsimile [6]. A companion document [4] describes the relationship 128 and mapping between this schema and Group 3 fax capabilities. 130 1.1 Organization of this document 132 Section 2 specifies the overall syntax for fax feature descriptions 133 by reference to the media feature registration and syntax documents 134 [1,2]. 136 Section 3 enumerates the feature tags that are to be recognized and 137 processed by extended Internet fax systems, according to their 138 capabilities. 140 Appendix A contains additional feature tag registrations for media 141 features that are specific to fax and for which no applicable 142 registration already exists. These are presented in the form 143 prescribed by the media feature registration procedure [1]. 145 1.2 Terminology and document conventions 147 The term "extended Internet fax system" is used to describe any 148 software, device or combination of these that conforms to the 149 specification "Extended Facsimile Using Internet Mail" [5]. 151 "capability exchange" describes any transfer of information between 152 communicating systems that is used to indicate system capabilities 153 and hence determine the form of data transferred. This term covers 154 both one-way and two-way transfers of capability information. 156 "capability identification" is a particular form of capability 157 exchange in which a receiving system provides capability 158 information to a sending system. 160 RFC nnnn Content feature schema for Internet fax 161 8 January 199 163 "capability description" is a collection of data presented in some 164 specific format that describes the capabilities of some 165 communicating entity. It may exist separately from any specific 166 capability exchange mechanism. 168 NOTE: Comments like this provide additional nonessential 169 information about the rationale behind this document. 170 Such information is not needed for building a conformant 171 implementation, but may help those who wish to understand 172 the design in greater depth. 174 2. Fax feature schema syntax 176 The syntax for the fax feature schema is described by "A syntax for 177 describing media feature sets" [2]. This in turn calls upon media 178 feature tags that may be registered according to the procedure 179 described in "Media Feature Tag Registration Procedure" [1]. 181 NOTE: Media feature registration provides a base 182 vocabulary of features that correspond to media handling 183 capabilities. The feature set syntax provides a 184 mechanism and format for combining these to describe 185 combinations of features. This memo indicates those 186 features that may be associated with extended Internet 187 fax systems. 189 3. Internet fax feature tags 191 This section enumerates and briefly describes a number of feature 192 tags that are defined for use with extended Internet fax systems 193 and applications. These tags may be used also by other systems and 194 applications that support corresponding capabilities. 196 The feature tags presented below are those that an extended 197 Internet fax system is expected to recognize its ability or non- 198 ability to handle. 200 Definitive descriptions of feature tags are indicated by reference 201 to their registration per the media feature registration procedure 202 [1] (some of which are appended to this document) 204 NOTE: The presence of a feature tag in this list does 205 not mean that an extended Internet fax system must have 206 that capability; rather, it must recognize the feature 207 tag and deal with it according to the capabilities that 208 it does have. 210 RFC nnnn Content feature schema for Internet fax 211 8 January 199 213 Further, an extended Internet fax system is not prevented 214 from recognizing and offering additional feature tags. 215 The list below is intended to provide a basic vocabulary 216 that all extended Internet fax systems can use in a 217 consistent fashion. 219 If an unrecognized or unused feature tag is received, the 220 feature set matching rule (described in [2]) operates so 221 that tag is effectively ignored. 223 3.1 Image size 225 Feature tag name Legal values 226 ---------------- ------------ 227 size-x (>0) 228 size-y (>0) 230 Reference: this document, Appendix A. 232 These feature values indicate a rendered document size in inches. 234 Where the actual size is measured in millimetres, a conversion 235 factor of 10/254 may be applied to yield an exact inch-based value. 237 3.2 Resolution 239 Feature tag name Legal values 240 ---------------- ------------ 241 dpi (>0) 242 dpi-xyratio (>0) 244 Reference: "Media Features for Display, Print, and Fax" [3], and 245 this document appendix A. 247 If 'dpi-xyratio' is present and not equal to 1 then the horizontal 248 resolution (x-axis) is indicated by the 'dpi' feature value, and 249 the vertical resolution (y-axis) is the value of 'dpi' divided by 250 'dpi-xyratio'. 252 For example, the basic Group 3 fax resolution of 200*100dpi might 253 be indicated as: 255 (& (dpi=200) (dpi-xyratio=200/100) ) 257 When describing resolutions for an MRC format document, the 258 complete set of usable resolutions is listed. However, there are 259 some restrictions on their use: (a) 100dpi resolution can be used 260 only with multi-level images, and (b) any multi-level image 261 resolution is required to be an integral sub-multiple of the 262 applicable mask resolution. 264 RFC nnnn Content feature schema for Internet fax 265 8 January 199 267 3.3 Media type 269 Feature tag name Legal values 270 ---------------- ------------ 271 ua-media screen 272 screen-paged 273 stationery 274 transparency 275 envelope 276 envelope-plain 277 continuous 279 Reference: "Media Features for Display, Print, and Fax" [3]. 281 NOTE: Where the recipient indicates specific support for 282 hard copy or soft copy media type, a sender of color 283 image data may wish to adjust the color components (e.g. 284 per the related rules of ITU recommendation T.42 [9]) to 285 improve rendered image quality on that medium. 287 3.4 Paper Size 289 Feature tag name Legal values 290 ---------------- ------------ 291 paper-size A4 292 A3 293 B4 294 letter 295 legal 297 Reference: "Media Features for Display, Print, and Fax" [3]. 299 RFC nnnn Content feature schema for Internet fax 300 8 January 199 302 3.5 Color capability 304 Feature tag name Legal values 305 ---------------- ------------ 306 color Binary (bi-level only) 307 Limited (a limited number of colors) 308 Mapped (palette or otherwise mapped color) 309 Grey (grey-scale only) 310 Full (full continuous-tone color) 312 Reference: "Media Features for Display, Print, and Fax" [3]. 314 The intention here is to give a broad indication of color handling 315 capabilities that might be used, for example, to select among a 316 small number of available data resources. 318 The value of this feature also gives an indication of the more 319 detailed color handling features that might be applicable (see next 320 section). 322 'Binary' indicates blank-and-white, or other bi-level capability. 323 No further qualifying feature tags are required. 325 'Limited' indicates a small number of distinct fixed colors, such 326 as might be provided by a highlight printer, pen plotter or limited 327 color display. The 'color-levels' tag should be used to indicate 328 the number of distinct colors available. 330 NOTE: No ability to indicate any specific or named color 331 is implied by this option. 333 Some devices might use different intensity levels rather 334 than different hues for distinction. 336 'Mapped' indicates that pixel color values are mapped in some 337 specifiable way to a multi-component color space. The 'color- 338 levels' tag may be used to indicate the number of distinct colors 339 available; in its absence, sufficient levels to display a 340 photographic image should be assumed. 342 'Grey' indicates a continuous tone grey-scale capability. 344 'Full' indicates full continuous tone color capability. 346 For 'Mapped', 'Grey' and 'Full' color, additional feature tags 347 (section 3.6) may be used to further qualify the color 348 reproduction. 350 RFC nnnn Content feature schema for Internet fax 351 8 January 199 353 3.6 Color model 355 Feature tag name Legal values 356 ---------------- ------------ 357 color-levels (>2) 358 color-space Device-RGB (device RGB) 359 Device-CMY (device CMY) 360 Device-CMYK (device CMYK) 361 CIELAB (LAB per T.42 [9]) 362 (may be extended by further registrations) 363 CIELAB-L-depth (>0) 364 CIELAB-a-depth 365 CIELAB-b-depth 366 CIELAB-L-min 367 CIELAB-L-max 368 CIELAB-a-min 369 CIELAB-a-max 370 CIELAB-b-min 371 CIELAB-b-max 373 Reference: this document, appendix A. 375 The general model for image handling (both color and non-color) is 376 described here from a receiver's perspective; a similar model 377 operates in the reverse direction for a scan/send perspective: 379 raw bit pixel color physical 380 stream -(A)-> values -(B)-> values -(C)-> rendition 382 - "raw bit stream" is a stream of coded bits 384 (A) indicates image coding/decoding (MH,MR,MMR,JPEG,JBIG,etc.) 386 - "pixel values" are a single numeric value per picture element 387 that designates the color of that element. 389 (B) indicates pixel-to-color value mapping 391 - "color values" have a separate numeric value for each color 392 component (i.e. L*, a*, b* in the case of CIELAB indicated 393 above.) 395 (C) indicates how the color values are related to a physical 396 color. This involves interpretation of the color value with 397 respect to a color model (e.g. RGB, L*a*b*, CMY, CMYK) and a 398 color space (which is typically recipient-dependent). 400 - "physical rendition" is a color value physically realized on a 401 display, printer or other device. 403 RFC nnnn Content feature schema for Internet fax 404 8 January 199 406 There are many variables that can be applied at each stage of the 407 processing of a color image, and any may be critical to meaningful 408 handling of that image in some circumstances. In other 409 circumstances many of the variables may be implied (to some level 410 of approximation) in the application that uses them (e.g. color 411 images published on a Web page). 413 The color feature framework described here is intended to allow 414 capability description at a range of granularity: feature tags 415 which correspond to implied (or "don't care" or "unknown") feature 416 values may simply be omitted from a capability description. 418 Grey scale and bi-level images are handled within this framework as 419 a special case, having a 1-component color model. The following 420 features are used for describing color capabilities: 422 'color-levels' indicates the number of distinct values for each 423 picture element, and applies to all but bi-level images. For bi- 424 level images, a value of 2 is implied. 426 'color-space' is used mainly with 'Mapped' and 'Full', but could be 427 used with other modes if the exact color used is significant. Two 428 kinds of color space can be distinguished: device-dependent and 429 calibrated. Device dependent spaces are named here as 'Device- 430 xxx', and are used to indicate a color space that is defined by the 431 receiving device. Calibrated color spaces presume the existence of 432 a rendering system that is calibrated with respect to an indicated 433 definition, and is capable of processing the device-independent 434 color information accordingly. 436 A color-handling receiver should indicate any appropriate device 437 color space capability in addition to any calibrated color spaces 438 that it may support. A calibrated color space should be used when 439 precise color matching is required in the absence of specific 440 knowledge of the receiving system. 442 NOTE: In practice, although they appear to be separate 443 concepts, the color model and color space cannot be 444 separated. In the final analysis, a color model (RGB, 445 CMY, etc.) must be defined with respect to some color 446 space. 448 'CIELAB-L-depth', 'CIELAB-a-depth' and 'CIELAB-b-depth' indicate 449 the number of different values that are possible for the L*, a* and 450 b* color components respectively, and are significant only when 451 colors are represented in a CIELAB color space. These features 452 would be used with palettized color, or with full color where each 453 color component has a different number of possible values. 455 RFC nnnn Content feature schema for Internet fax 456 8 January 199 458 The 'CIELAB-x-min' and 'CIELAB-x-max' values indicate a color gamut 459 (i.e. a range of color values that are used or may be rendered). A 460 gamut may be indicated in terms of the CIELAB color space even when 461 colors are represented in some other space. 463 3.7 Image coding 465 Feature tag name Legal values 466 ---------------- ------------ 467 image-file- TIFF-S 468 structure TIFF-F 469 TIFF-J 470 TIFF-C 471 TIFF-L 472 TIFF-M 473 (may be extended by further registrations, 474 to cover non-TIFF image file structures) 475 image-coding MH 476 MR 477 MMR 478 JBIG 479 JPEG 480 (may be extended by further registrations) 481 image-coding- JBIG-T85 (bi-level, per ITU T.85) 482 constraint JBIG-T43 (multi-level, per ITU T.43) 483 JPEG-T4E (per ITU T.4, Annex E) 484 (may be extended by further registrations) 485 JBIG-stripe-size 486 image-interleave Stripe 487 Plane 488 color-subsampling "1:1:1" (no color subsampling) 489 "4:1:1" (4:1:1 color subsampling) 490 MRC-mode (0..7) (per ITU T.44 [15]) 491 MRC-max-stripe-size 493 Reference: this document, appendix A. 495 'image-file-structure' defines how the coded image data is wrapped 496 and formatted. Options defined here are the various profiles of 497 TIFF-FX, per RFC 2301 [7]. These options apply to overall 498 formatting of the image data (TIFF file format, byte ordering, bit 499 ordering, etc.) and do not define specific image coding issues that 500 are covered by other aspects of the TIFF-FX profile specifications. 502 'image-coding' describes how the raw image data is compressed and 503 coded as a sequence of bits. These are generic tags that may apply 504 to a range of file formats and usage environments. 506 RFC nnnn Content feature schema for Internet fax 507 8 January 199 509 'image-coding-constraint' describes how the raw image data coding 510 method is constrained to meet a particular operating environment. 511 Options defined here are JBIG and JPEG coding constraints that 512 apply in typical Group 3 fax environments. 514 The 'JBIG-stripe-size' feature may be used with JBIG image coding, 515 and indicates the number of scan lines in each stripe except the 516 last in an image. The legal constraints are: 518 (JBIG-stripe-size=128) 519 (JBIG-stripe-size>=0) 521 The latter being equivalent to no restriction. 523 The 'MRC-mode' feature is used to indicate the availability of MRC 524 (mixed raster content) image format capability, and also the MRC 525 mode available. A zero value indicates MRC is not available, a 526 non-zero value indicates the available MRC mode number. 528 An MRC formatted document is actually a collection of several 529 images, each of which is described by a separate feature 530 collection. An MRC-capable receiver is presumed to be capable of 531 accepting any combination of contained images that conform to the 532 MRC construction rules and declared image-coding capabilities. 534 Within an MRC-formatted document, multi-level coders are used for 535 foreground and background images (i.e. odd-numbered layers: 1, 3, 536 5, etc.) and bi-level coders are used for mask layers (i.e. even 537 numbered layers 2, 4, 6, etc.). 539 NOTE: an MRC formatted document may appear within a TIFF 540 image file structure, so this separate feature is needed 541 to capture the full range of possible capabilities. 543 The 'MRC-max-stripe-size' feature may be used with MRC coding, and 544 indicates the maximum number of scan lines in each MRC stripe. The 545 legal constraints are: 547 (MRC-max-stripe-size=[0..256]) 548 (MRC-max-stripe-size>=0) 550 These values indicate upper bounds on the stripe size. The actual 551 value may vary between stripes, and the actual size for each stripe 552 is indicated in the image data. 554 RFC nnnn Content feature schema for Internet fax 555 8 January 199 557 NOTE: there are many image coding options here, and not 558 all are required in all circumstances. 560 Specification of the image-file-structure tag value alone 561 is not normally sufficient to describe the capabilities 562 of a recipient. A general rule is that sufficient detail 563 should be provided to exclude any unsupported features. 565 For extended Internet fax, image-file-structure and 566 image-coding should always be specified, together with 567 additional values described above as needed to clearly 568 indicate which feature tag values are supported and which 569 are not. (See also the examples in section 4.) 571 4. Examples 573 Some of the examples contain comments introduced by '--...'. These 574 are not part of the allowed capability description syntax. They 575 are included here to explain some of the constructs used. 577 The level of detail captured here reflects that used for capability 578 identification in Group 3 facsimile. 580 4.1 Simple mode Internet fax system 582 This example describes the capabilities of a typical simple mode 583 Internet fax system. Note that TIFF application S is required to 584 be supported by such a system. 586 (& (color=Binary) 587 (image-file-structure=TIFF-S) 588 (dpi=200) 589 (dpi-xyratio=[200/100,200/200]) 590 (paper-size=A4) 591 (image-coding=MH) (MRC-mode=0) 592 (ua-media=stationery) ) 594 RFC nnnn Content feature schema for Internet fax 595 8 January 199 597 4.2 High-end black-and-white Internet fax system 599 This would include support for B/W JBIG and be equivalent to what 600 is sometimes called "Super G3", except that Internet fax 601 functionality would be added. 603 (& (color=Binary) 604 (image-file-structure=[TIFF-S,TIFF-F,TIFF-J]) 605 (| (& (dpi=200) (dpi-xyratio=200/100) ) -- 200*100 606 (& (dpi=200) (dpi-xyratio=1) ) -- 200*200 607 (& (dpi=204) (dpi-xyratio=204/391) ) -- 204*391 608 (& (dpi=300) (dpi-xyratio=1) ) ) -- 300*300 609 (| (image-coding=[MH,MR,MMR]) 610 (& (image-coding=JBIG) 611 (image-coding-constraint=JBIG-T85) 612 (JBIG-stripe-size=128) ) ) 613 (MRC-mode=0) 614 (paper-size=[A4,B4]) ) 616 4.3 Grey-scale Internet fax system 618 This is the previous example extended to handle grey scale multi- 619 level images. In keeping with Group 3 fax, this example requires 620 equal x- and y- resolutions for a multi-level image. 622 (& (| (& (color=Binary) 623 (image-file-structure=[TIFF-S,TIFF-F,TIFF-J]) 624 (| (image-coding=[MH,MR,MMR]) 625 (& (image-coding=JBIG) 626 (image-coding-constraint=JBIG-T85) 627 (JBIG-stripe-size=128) ) ) 628 (| (& (dpi=200) (dpi-xyratio=200/100) ) 629 (& (dpi=200) (dpi-xyratio=1) ) 630 (& (dpi=204) (dpi-xyratio=204/391) ) 631 (& (dpi=300) (dpi-xyratio=1) ) ) ) 632 (& (color=Grey) 633 (image-file-structure=[TIFF-C,TIFF-L]) 634 (color-levels<=256) 635 (color-space-CIELAB) 636 (| (& (image-coding=JPEG) 637 (image-coding-constraint=JPEG-T4E) ) 638 (& (image-coding=JBIG) 639 (image-coding-constraint=JBIG-T43) 640 (JBIG-stripe-size=128) 641 (image-interleave=stripe) ) ) 642 (dpi=[100,200,300]) 643 (dpi-xyratio=1) ) ) 644 (MRC-mode=0) 645 (paper-size=[A4,B4]) ) 647 RFC nnnn Content feature schema for Internet fax 648 8 January 199 650 4.4 Full-color Internet fax system 652 This adds 16-bit full-color to the previous example. 654 (& (| (& (color=Binary) 655 (image-file-structure=[TIFF-S,TIFF-F,TIFF-J]) 656 (| (image-coding=[MH,MR,MMR]) 657 (& (image-coding=JBIG) 658 (image-coding-constraint=JBIG-T85) 659 (JBIG-stripe-size=128) ) ) 660 (| (& (dpi=200) (dpi-xyratio=200/100) ) 661 (& (dpi=200) (dpi-xyratio=1) ) 662 (& (dpi=204) (dpi-xyratio=204/391) ) 663 (& (dpi=300) (dpi-xyratio=1) ) ) ) 664 (& (| (& (color=Grey) (color-levels<=256) ) 665 (& (color=Full) (color-levels<=65536) 666 (color-subsampling=["1:1:1","4:1:1"]) ) ) 667 (image-file-structure=[TIFF-C,TIFF-L]) 668 (color-space=CIELAB) 669 (| (& (image-coding=JPEG) 670 (image-coding-constraint=JPEG-T4E) ) 671 (& (image-coding=JBIG) 672 (image-coding-constraint=JBIG-T43) 673 (JBIG-stripe-size=128) 674 (image-interleave=stripe) ) ) 675 (dpi=[100,200,300]) 676 (dpi-xyratio=1) ) ) 677 (MRC-mode=0) 678 (paper-size=[A4,B4]) ) 680 RFC nnnn Content feature schema for Internet fax 681 8 January 199 683 4.5 Full-color Internet fax system (MRC) 685 (& (| (& (color=Binary) 686 (image-file-structure=[TIFF-S,TIFF-F,TIFF-J]) 687 (MRC-mode=0) 688 (image-coding=[MH,MMR]) 689 (| (& (dpi=200) (dpi-xyratio=[200/100,1]) ) 690 (& (dpi=204) (dpi-xyratio=204/391) ) 691 (& (dpi=300) (dpi-xyratio=1) ) 692 (& (dpi=400) (dpi-xyratio=1) ) ) ) 693 (& (image-file-structure=[TIFF-C,TIFF-L]) 694 (| (& (color=Grey) (color-levels<=256) ) 695 (& (color=Full) (color-levels<=65536) 696 (color-subsampling=["1:1:1","4:1:1"]) ) ) 697 (color-space=CIELAB) 698 (MRC-mode=0) 699 (image-coding=JPEG) 700 (image-coding-constraint=JPEG-T4E) 701 (dpi=[100,200,300,400]) 702 (dpi-xyratio=1) ) 703 (& (image-file-structure=TIFF-M) 704 (MRC-mode=1) (MRC-max-stripe-size=[0..256]) 705 (image-coding=[MH,MMR,JPEG]) 706 (| (color=Binary) 707 (& (color=Grey) (color-levels<=256) ) 708 (& (color=Full) (color-levels<=65536) 709 (color-subsampling=["1:1:1","4:1:1"]) ) ) 710 (color-space=CIELAB) 711 (dpi=[100,200,300,400]) 712 (dpi-xyratio=1) ) ) 713 (paper-size=[A4,B4]) ) 715 4.6 Sender and receiver feature matching 717 This example considers sending a document to a high-end black-and- 718 white fax system with the following receiver capabilities: 720 (& (| (& (dpi=200) (dpi-xyratio=200/100) ) -- 200*100 721 (& (dpi=200) (dpi-xyratio=1) ) -- 200*200 722 (& (dpi=300) (dpi-xyratio=1) ) -- 300*300 723 (& (dpi=400) (dpi-xyratio=1) ) ) -- 400*400 724 (color=Binary) 725 (| (& (paper-size=A4) (ua-media=[stationery,transparency]) ) 726 (& (paper-size=B4) (ua-media=continuous) ) ) 727 (image-coding=[MH,MR,JBIG]) ) 729 RFC nnnn Content feature schema for Internet fax 730 8 January 199 732 Turning to the document itself, assume it is available to the 733 sender in three possible formats, A4 high resolution, B4 low 734 resolution and A4 high resolution color, described by: 736 (& (dpi=300) (dpi-xyratio=1) 737 (color=Binary) 738 (paper-size=A4) 739 (image-coding=[MMR,JBIG]) ) 741 (& (dpi=200) (dpi-xyratio=200/100) 742 (color=Binary) 743 (paper-size=B4) 744 (image-coding=[MH,MR]) ) 746 (& (dpi=300) (dpi-xyratio=1) 747 (color=Mapped) (color-levels<=256) 748 (paper-size=A4) 749 (image-coding=JPEG) ) 751 These three image formats can be combined into a composite 752 capability statement by a logical-OR operation (to describe 753 format-1 OR format-2 OR format-3): 755 (| (& (dpi=300) (dpi-xyratio=1) 756 (color=Binary) 757 (paper-size=A4) 758 (image-coding=[MMR,JBIG]) ) 759 (& (dpi=200) (dpi-xyratio=200/100) 760 (color=Binary) 761 (paper-size=B4) 762 (image-coding=[MH,MR]) ) 763 (& (dpi=300) (dpi-xyratio=1) 764 (color=Mapped) (color-levels=42) 765 (paper-size=A4) 766 (image-coding=JPEG) ) ) 768 This could be simplified, but there is little gain in doing so at 769 this point. 771 RFC nnnn Content feature schema for Internet fax 772 8 January 199 774 The composite document description can be matched with the receiver 775 capability description, according to the rules in [2], to yield the 776 result: 778 (| (& (dpi=300) (dpi-xyratio=1) 779 (color=Binary) 780 (paper-size=A4) 781 (ua-media=[stationery,transparency]) 782 (image-coding=JBIG) ) 783 (& (dpi=200) (dpi-xyratio=200/100) 784 (color=Binary) 785 (paper-size=B4) 786 (ua-media=continuous) 787 (image-coding=[MH,MR]) ) ) 789 Points to note about the feature matching process: 791 o The color document option is eliminated because the receiver 792 cannot handle either color (indicated by '(color=Mapped)') or 793 JPEG coding (indicated by '(image-coding=JPEG)'). 795 o The high resolution version of the document with '(dpi=300)' must 796 be send using '(image-coding=JBIG)' because this is the only 797 available coding of the image data that the receiver can use for 798 high resolution documents. (The available 300dpi document 799 codings here are MMR and JBIG, and the receiver capabilities are 800 MH, MR and JBIG.) 802 o The low-resolution version of the document can be sent with 803 either MH or MR coding as the receiver can deal with either of 804 these for low resolution documents. 806 o The high resolution variant of the document is available only for 807 A4, so that is the paper-size used in that case. Similarly the 808 low resolution version is sent for B4 paper. 810 o Even though the sender may not understand the 'ua-media' feature 811 tag, and does not mention it, the matching rules preserve the 812 constraint that the B4 document is rendered with 813 '(ua-media=continuous)', and the A4 document may be rendered with 814 '(ua-media=[stationery,transparency])'. 816 Finally, note that when matching an MRC document description, the 817 description of each component sub-image must match the capabilities 818 of the intended receiver. 820 RFC nnnn Content feature schema for Internet fax 821 8 January 199 823 5. IANA considerations 825 Appendix A of this document calls for registrations of feature tags 826 in the "IETF tree", as defined in section 3.1.1 of "Media Feature 827 Tag Registration Procedure" [1] (i.e. these feature tags are 828 subject to the "IETF Consensus" policies described in RFC 2434 829 [21]). 831 ASN.1 identifiers should be assigned for each of these registered 832 feature tags and replaced in the body of the registration. 834 6. Security considerations 836 The points raised below are in addition to the general security 837 considerations for extended Internet fax [5], and others discussed 838 in [2,8,11,12,13] 840 6.1 Capability descriptions and mechanisms 842 Negotiation mechanisms reveal information about one party to other 843 parties. This may raise privacy concerns, and may allow a 844 malicious party to make better guesses about the presence of 845 specific security holes. 847 Most of these concerns pertain to capability information getting 848 into the hands of someone who may abuse it. This document 849 specifies capabilities that help a sender to determine what image 850 characteristics can be processed by the recipient, not mechanisms 851 for their publication. Implementors and users should take care 852 that the mechanisms employed ensure that capabilities are revealed 853 only to appropriate persons, systems and agents. 855 6.2 Specific threats 857 1. Unsolicited bulk mail: if it is known that a recipient can 858 process certain types of images, they may be targeted by bulk 859 mailers that want to send such images. 861 RFC nnnn Content feature schema for Internet fax 862 8 January 199 864 7. Full copyright statement 866 Copyright (C) The Internet Society 1999. All Rights Reserved. 868 This document and translations of it may be copied and furnished to 869 others, and derivative works that comment on or otherwise explain 870 it or assist in its implementation may be prepared, copied, 871 published and distributed, in whole or in part, without restriction 872 of any kind, provided that the above copyright notice and this 873 paragraph are included on all such copies and derivative works. 874 However, this document itself may not be modified in any way, such 875 as by removing the copyright notice or references to the Internet 876 Society or other Internet organizations, except as needed for the 877 purpose of developing Internet standards in which case the 878 procedures for copyrights defined in the Internet Standards process 879 must be followed, or as required to translate it into languages 880 other than English. 882 The limited permissions granted above are perpetual and will not be 883 revoked by the Internet Society or its successors or assigns. 885 This document and the information contained herein is provided on 886 an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET 887 ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR 888 IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 889 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 890 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 892 8. Acknowledgements 894 The authors gratefully acknowledge the contributions of the 895 following persons who commented on earlier versions of this memo: 896 James Rafferty, Dan Wing, Robert Buckley, Mr Ryuji Iwazaki. The 897 following contributed ideas upon which some of the features 898 described here have been based: Larry Masinter, Al Gilman, Koen 899 Holtman. 901 9. References 903 [1] "Media Feature Tag Registration Procedure" 904 Koen Holtman, TUE 905 Andrew Mutz, Hewlett-Packard 906 Ted Hardie, NASA 907 Internet draft: 908 Work in progress, July 1998. 910 [2] "A syntax for describing media feature sets" 911 Graham Klyne, 5GM/Content Technologies 912 Internet draft: " 913 Work in progress, September 1998. 915 RFC nnnn Content feature schema for Internet fax 916 8 January 199 918 [3] "Media Features for Display, Print, and Fax" 919 Larry Masinter, Xerox PARC 920 Koen Holtman, TUE 921 Andrew Mutz, Hewlett-Packard 922 Dan Wing, Cisco Systems 923 Internet draft: 924 Work in progress, September 1998. 926 [4] "Internet fax feature mapping from Group 3 fax" 927 Lloyd McIntyre, Xerox Corporation 928 Graham Klyne, 5GM/Content Technologies 929 Internet draft: 930 Work in progress, August 1998. 932 [5] "Extended Facsimile Using Internet Mail 933 Larry Masinter, Xerox Corporation 934 Dan Wing, Cisco Systems 935 Internet draft: 936 Work in progress, September 1998. 938 [6] "Procedures for document facsimile transmission in the general 939 switched telephone network" 940 ITU-T Recommendation T.30 (1996) 941 International Telecommunications Union 942 July 1996 944 [7] RFC 2301, "File format for Internet fax" 945 L. McIntyre, 946 R. Buckley, 947 D. Venable, Xerox Corporation 948 S. Zilles, Adobe Systems, Inc. 949 G. Parsons, Northern Telecom 950 J. Rafferty, Human Communications 951 March 1998. 953 [8] RFC 2305, "A Simple Mode of Facsimile Using Internet Mail" 954 K. Toyoda 955 H. Ohno 956 J. Murai, WIDE Project 957 D. Wing, Cisco Systems 958 March 1998. 960 [9] "Continuous-tone color representation method for facsimile" 961 ITU-T Recommendation T.42 (1996) 962 International Telecommunications Union 963 (Covers custom illuminant, gamut) 965 RFC nnnn Content feature schema for Internet fax 966 8 January 199 968 [10] "Colour and gray-scale image representation using lossless coding 969 scheme for facsimile" 970 ITU-T Recommendation T.43 (1997) 971 International Telecommunications Union. 972 (Covers JBIG for colour/grey images) 974 [11] "Scenarios for the Delivery of Negotiated Content" 975 T. Hardie, NASA Network Information Center 976 Internet draft: 977 Work in progress, November 1997. 979 [12] "Requirements for protocol-independent content negotiation" 980 G. Klyne, Integralis Ltd. 981 Internet draft: 982 Work in progress, March 1998. 984 [13] "Standardization of Group 3 facsimile terminals for document 985 transmission" 986 ITU-T Recommendation T.4 (1996) 987 International Telecommunications Union 988 (Covers basic fax coding formats: MH, MR) 990 [14] "Facsimile coding schemes and coding control functions for Group 991 4 facsimile apparatus" 992 ITU Recommendation T.6 993 International Telecommunications Union 994 (Commonly referred to as the MMR standard; covers extended 2-D 995 fax coding format) 997 [15] "Mixed Raster Content (MRC)" 998 ITU-T Recommendation T.44 999 International Telecommunications Union 1001 [16] "Information technology - Digital compression and coding of 1002 continuous-tone still image - Requirements and guidelines" 1003 ITU-T Recommendation T.81 (1992) | ISO/IEC 10918-1:1993 1004 International Telecommunications Union 1005 (Commonly referred to as JPEG standard) 1007 [17] "Information technology - Coded representation of picture and 1008 audio information - Progressive bi-level image compression" 1009 ITU-T Recommendation T.82 (1993) | ISO/IEC 11544:1993 1010 International Telecommunications Union 1011 (Commonly referred to as JBIG1 standard) 1013 RFC nnnn Content feature schema for Internet fax 1014 8 January 199 1016 [18] "Application profile for Recommendation T.82 - Progressive bi- 1017 level image compression (JBIG1 coding scheme for facsimile 1018 apparatus)" 1019 ITU-T Recommendation T.85 (1995) 1020 International Telecommunications Union 1021 (Covers bi-level JBIG) 1023 [19] "Colorimeter, 2nd ed." 1024 CIE Publication No. 15.2 1025 1986. 1026 (Defines CIELAB color space; use with fax is further constrained 1027 by T.42 [9].) 1029 [20] Tag Image File Format, Revision 6.0 1030 Adobe Developers Association 1031 1033 June 1992 1035 [21] RFC 2434, "Guidelines for Writing an IANA Considerations Section 1036 in RFCs" 1037 T. Narten, IBM 1038 H. Alvestrand, Maxware 1039 October 1998. 1041 10. Authors' addresses 1043 Graham Klyne 1044 5th Generation Messaging Ltd. Content Technologies Ltd. 1045 5 Watlington Street Forum 1, Station Road 1046 Nettlebed Theale 1047 Henley-on-Thames, RG9 5AB Reading, RG7 4RA 1048 United Kingdom United Kingdom. 1049 Telephone: +44 1491 641 641 +44 118 930 1300 1050 Facsimile: +44 1491 641 611 +44 118 930 1301 1051 E-mail: GK@ACM.ORG 1053 Lloyd McIntyre 1054 Xerox Corporation 1055 Mailstop PAHV-121 1056 3400 Hillview Ave. 1057 Palo Alto, CA 94304 USA 1058 Telephone: +1-650-813-6762 1059 Facsimile: +1-650-845-2340 1060 E-mail: Lloyd.McIntyre@pahv.xerox.com 1062 RFC nnnn Content feature schema for Internet fax 1063 8 January 199 1065 Appendix A: Feature registrations 1067 A.1 Image size 1069 - Media Feature tag name(s): 1071 size-x 1072 size-y 1074 - ASN.1 identifiers associated with these feature tags: 1076 [[[New assignments by IANA]]] 1078 - Summary of the media features indicated: 1080 These feature tags indicate the size of a displayed, printed 1081 or otherwise rendered document image; they indicate 1082 horizontal (size-x) and vertical (size-y) dimensions. 1084 The unit of measure is inches (to be consistent with the 1085 measure of resolution defined by the feature tag 'dpi'). 1087 Where the actual size is available in millimetres, a 1088 conversion factor of 10/254 may be applied to yield an exact 1089 inch-based value. 1091 - Values appropriate for use with these feature tags: 1093 Rational (>0) 1095 - The feature tag is intended primarily for use in the following 1096 applications, protocols, services, or negotiation mechanisms: 1098 Print and display applications where different media choices 1099 will be made depending on the size of the recipient device. 1101 - Examples of typical use: 1103 This example describes the maximum scanned image width and 1104 height for Group 3 fax: 215x297 mm (8.46x11.69 inches): 1106 (size-x<=2150/254) 1107 (size-y<=2970/254) 1109 RFC nnnn Content feature schema for Internet fax 1110 8 January 199 1112 - Related standards or documents: 1114 The memo "Media Features for Display, Print, and Fax" [3] 1115 describes features (pix-x, pix-y) for measuring document size 1116 in pixels. 1118 Fax applications should declare physical dimensions using the 1119 features defined here. 1121 - Considerations particular to use in individual applications, 1122 protocols, services, or negotiation mechanisms: 1124 Where no physical size is known or available, but a pixel size 1125 is known, a notional size should be declared based upon known 1126 pixel dimensions and a notional resolution of (say) 100dpi 1128 For example, to describe a 640x480 pixel display: 1130 (& (size-x<=640/100) (size-y<=480/100) (dpi=100) ) 1132 The notional 100dpi resolution is used as it represents a 1133 fairly typical resolution for a pixel-limited display. 1134 Reducing the rational numbers to canonical form gives the 1135 following equivalent expression: 1137 (& (size-x<=32/5) (size-y<=24/5) (dpi=100) ) 1139 - Interoperability considerations: 1141 For interoperability with other (non-fax) applications that 1142 use only pixel-based measurements, pixel dimensions (pix-x, 1143 pix-y) may be declared in addition to physical measurements. 1145 - Related feature tags: 1147 pix-x [3] 1148 pix-y [3] 1149 dpi [3] 1150 dpi-xyratio [this document] 1152 - Intended usage: 1154 Common 1156 - Author/Change controller: 1158 IETF 1160 RFC nnnn Content feature schema for Internet fax 1161 8 January 199 1163 A.2 Resolution aspect ratio 1165 - Media Feature tag name(s): 1167 dpi-xyratio 1169 - ASN.1 identifier associated with this feature tag: 1171 [[[New assignments by IANA]]] 1173 - Summary of the media features indicated: 1175 This feature is used to indicate differential horizontal and 1176 vertical resolution capability. In the absence of this 1177 feature, horizontal and vertical resolutions are presumed to 1178 be the same. 1180 When this feature tag is specified, any declared resolution 1181 (dpi) is presumed to apply to the horizontal axis, and the 1182 vertical resolution is obtained by dividing that declared 1183 resolution by the resolution ratio. 1185 The value of this feature is a pure number, since it 1186 represents the ratio of two resolution values. 1188 - Values appropriate for use with this feature tag: 1190 Rational (>0) 1192 - The feature tag is intended primarily for use in the following 1193 applications, protocols, services, or negotiation mechanisms: 1195 Internet fax, and other print or display applications that 1196 must handle differential horizontal and vertical resolution 1197 values. 1199 - Examples of typical use: 1201 The following example describes a fax resolution of 204 dpi 1202 horizontally by 391 dpi vertically: 1204 (& (dpi=204) (dpi-xyratio=204/391) ) 1206 - Related standards or documents: 1208 The memo "Media Features for Display, Print, and Fax" [3] 1209 describes a feature (dpi) for measuring document resolution. 1211 RFC nnnn Content feature schema for Internet fax 1212 8 January 199 1214 - Interoperability considerations: 1216 When interoperating with an application that does not 1217 recognize the differential resolution feature, resolution 1218 matching may be performed on the basis of the horizontal 1219 resolution only, so aspect ratio information may be lost. 1221 - Related feature tags: 1223 dpi [3] 1224 size-x [this document] 1225 size-y [this document] 1227 - Intended usage: 1229 Internet fax 1231 - Author/Change controller: 1233 IETF 1235 RFC nnnn Content feature schema for Internet fax 1236 8 January 199 1238 A.3 Color levels 1240 - Media Feature tag name(s): 1242 color-levels 1244 - ASN.1 identifier associated with this feature tag: 1246 [[[New assignments by IANA]]] 1248 - Summary of the media features indicated: 1250 This feature tag is used to indicate a number of different 1251 image data pixel color values. 1253 When mapped (palettized) color is used, this is generally 1254 different from the number of different colors that can be 1255 represented through the color mapping function. 1257 This feature tag is used in conjunction with a 'color' feature 1258 having a value other than 'Binary'. 1260 - Values appropriate for use with this feature tag: 1262 Integer (>=2) 1264 - The feature tag is intended primarily for use in the following 1265 applications, protocols, services, or negotiation mechanisms: 1267 Color image printing or display applications where the data 1268 resource used may depend upon color handling capabilities of 1269 the recipient. 1271 - Examples of typical use: 1273 To describe recipient capabilities: 1274 (& (color=limited) (color-levels<=6) ) 1275 (& (color=grey) (color-levels<=64) ) 1276 (& (color=mapped) (color-levels<=240) ) 1277 (& (color=full) (color-levels<=16777216) ) 1279 To describe capabilities used by a document: 1280 (& (color=limited) (color-levels=4) ) 1281 (& (color=grey) (color-levels=48) ) 1282 (& (color=mapped) (color-levels=100) ) 1283 (& (color=full) (color-levels=32768) ) 1285 RFC nnnn Content feature schema for Internet fax 1286 8 January 199 1288 - Related standards or documents: 1290 The memo "Media Features for Display, Print, and Fax" [3] 1291 describes a feature (color) for indicating basic color 1292 capabilities. 1294 - Interoperability considerations: 1296 The actual number of color values used by a document does not, 1297 in general, exactly match the number that can be handled by a 1298 recipient. To achieve a feature match, at least one must be 1299 declared as an inequality. 1301 It is recommended that a recipient declares the number of 1302 color values that it can handle as an inequality (<=), and a 1303 data resource declares the number of colors that it uses with 1304 an equality, as shown in the examples above. 1306 - Security considerations: 1308 - Privacy concerns, related to exposure of personal information: 1309 Where feature matching is used to select content applicable 1310 to the physical abilities of a user, unusual values for this 1311 feature tag might give an indication of a user's restricted 1312 abilities. 1314 - Related feature tags: 1316 color [3] 1317 color-space [this document] 1319 - Intended usage: 1321 Internet fax 1322 Color image scanning/rendering applications 1324 - Author/Change controller: 1326 IETF 1328 RFC nnnn Content feature schema for Internet fax 1329 8 January 199 1331 A.4 Color space 1333 - Media Feature tag name(s): 1335 color-space 1337 - ASN.1 identifier associated with this feature tag: 1339 [[[New assignments by IANA]]] 1341 - Summary of the media features indicated: 1343 This feature indicates a color space. 1345 A color space value provides two types of information: 1346 o the color model used to represent a color value, including 1347 the number of color components 1348 o a mapping between color values and their physical 1349 realizations 1351 Device color space values are defined for applications where 1352 the general color representation used is significant, but 1353 exact color rendering is left to the device used. Device 1354 color spaces defined here have values of the form 'Device- 1355 xxx'. 1357 Calibrated color space values are provided for use with a 1358 rendering system that is calibrated with respect to some 1359 indicated definition, and capable of processing device- 1360 independent color information accordingly. 1362 - Values appropriate for use with this feature tag: 1364 Token 1366 Device color Device-RGB (device dependent RGB) 1367 spaces: Device-CMY (device dependent CMY) 1368 Device-CMYK (device dependent CMYK) 1370 Calibrated color CIELAB (per T.42 [9]) 1371 space: 1373 (may be extended by further registrations) 1375 'Color-space=CIELAB' indicates the CIE L*a*b* colour space, 1376 using CIED50 illuminant and its perfectly diffuse reflecting 1377 white point (per T.42 [9]). 1379 RFC nnnn Content feature schema for Internet fax 1380 8 January 199 1382 - The feature tag is intended primarily for use in the following 1383 applications, protocols, services, or negotiation mechanisms: 1385 Color image printing and display applications where the data 1386 resource used may depend upon color handling capabilities of 1387 the recipient. 1389 Scanning applications where the data transferred may depend 1390 upon the image generation capabilities of the originator. 1392 - Examples of typical use: 1394 To describe rendering or scanning capabilities: 1396 (color-space=[Device-RGB,CIELAB]) 1398 To describe capabilities assumed by a document for which 1399 approximate color reproduction is required: 1401 (color-space=Device-RGB) 1403 To describe capabilities assumed by a document for which exact 1404 color reproduction is required: 1406 (color-space=CIELAB) 1408 - Related standards or documents: 1410 CIELAB color space is defined in [19] 1412 CIELAB use for fax is described in ITU T.42 [9] 1414 - Interoperability considerations: 1416 A color-handling receiver should indicate at any appropriate 1417 device color space capability, in addition to any calibrated 1418 color spaces that it may support. 1420 Calibrated color spaces are intended to be used when precise 1421 color matching is required; otherwise, if applicable, a 1422 device color space (color-space=Device-xxx) should be 1423 indicated. 1425 Documents for which exact color matching is not important 1426 should indicate a device color space capability, if 1427 applicable. 1429 These principles allow sender/receiver feature matching to be 1430 achieved when exact color matching is not required. 1432 RFC nnnn Content feature schema for Internet fax 1433 8 January 199 1435 - Security considerations: 1437 - Privacy concerns, related to exposure of personal information: 1438 Where feature matching is used to select content applicable 1439 to the physical abilities of a user, unusual values for this 1440 feature tag might give an indication of a user's restricted 1441 abilities. 1443 - Denial of service concerns related to consequences of 1444 specifying incorrect values: 1445 Failure to indicate a generic color space capability for a 1446 device may lead to failure to match color space for an 1447 application or document that does not require an exact color 1448 match. 1450 - Related feature tags: 1452 color [3] 1454 - Related media types or data formats: 1456 TIFF-FX [7] 1458 - Intended usage: 1460 Internet fax 1461 Color image scanning/rendering applications 1463 - Author/Change controller: 1465 IETF 1467 RFC nnnn Content feature schema for Internet fax 1468 8 January 199 1470 A.5 CIELAB color depth 1472 - Media Feature tag name(s): 1474 CIELAB-L-depth 1475 CIELAB-A-depth 1476 CIELAB-B-depth 1478 - ASN.1 identifiers associated with these feature tags: 1480 [[[New assignments by IANA]]] 1482 - Summary of the media features indicated: 1484 These feature tags indicate a color depth capability; i.e. 1485 the level of detail to which an individual CIELAB color 1486 component can be specified. They define the number of 1487 distinct values possible for each of the color components L*, 1488 a* and b*. 1490 Typically, this feature would be used with 'color=mapped', and 1491 possibly 'color=grey' or 'color=full', to indicate the number 1492 of distinct colors that can be realized. 1494 - Values appropriate for use with these feature tags: 1496 Integer (>0) 1498 - These feature tags are intended primarily for use in the 1499 following applications, protocols, services, or negotiation 1500 mechanisms: 1502 Color image printing and display applications where the data 1503 resource used may depend upon color handling capabilities of 1504 the recipient. 1506 Scanning applications where the data transferred may depend 1507 upon the image generation capabilities of the originator. 1509 RFC nnnn Content feature schema for Internet fax 1510 8 January 199 1512 - Examples of typical use: 1514 To describe rendering or scanning capabilities: 1516 (& (color=mapped) (color-levels<=240) 1517 (CIELAB-L-depth<=128) 1518 (CIELAB-a-depth<=128) 1519 (CIELAB-b-depth<=128) ) 1520 (& (color=full) (color-levels<=16777216) 1521 (CIELAB-L-depth<=256) 1522 (CIELAB-a-depth<=128) 1523 (CIELAB-b-depth<=128) ) 1525 To describe capabilities assumed by a document: 1527 (& (color=mapped) (color-levels=200) 1528 (CIELAB-L-depth=32) 1529 (CIELAB-a-depth=32) 1530 (CIELAB-b-depth=32) ) 1531 (& (color=full) (color-levels=32768) 1532 (CIELAB-L-depth=128) 1533 (CIELAB-a-depth=32) 1534 (CIELAB-b-depth=32) ) 1536 - Related standards or documents: 1538 The memo "Media Features for Display, Print, and Fax" [3] 1539 defines a feature (color) for indicating basic color 1540 capabilities. 1542 CIELAB color space is defined in [19] 1544 CIELAB use for fax is described in ITU T.42 [9] 1546 - Related feature tags: 1548 color [3] 1549 color-levels [this document] 1550 color-space [this document] 1552 - Intended usage: 1554 Internet fax 1555 Color image scanning/rendering applications 1557 - Author/Change controller: 1559 IETF 1561 RFC nnnn Content feature schema for Internet fax 1562 8 January 199 1564 A.6 CIELAB color gamut 1566 - Media Feature tag name(s): 1568 CIELAB-L-min 1569 CIELAB-L-max 1570 CIELAB-a-min 1571 CIELAB-a-max 1572 CIELAB-b-min 1573 CIELAB-b-max 1575 - ASN.1 identifiers associated with these feature tags: 1577 [[[New assignments by IANA]]] 1579 - Summary of the media features indicated: 1581 These feature indicate a supported range of color values, by 1582 indicating minimum and maximum values used for each color 1583 component in a CIELAB color space. 1585 'CIELAB-L-min' and 'CIELAB-L-max' are the minimum and maximum 1586 values of the L* component. 1588 'CIELAB-a-min' and 'CIELAB-a-max' are the minimum and maximum 1589 values of the a* component. 1591 'CIELAB-b-min' and 'CIELAB-b-max' are the minimum and maximum 1592 values of the b* component. 1594 - Values appropriate for use with this feature tag: 1596 Rational 1598 - The feature tag is intended primarily for use in the following 1599 applications, protocols, services, or negotiation mechanisms: 1601 Color image printing and display applications where the data 1602 resource used may depend upon detailed color handling 1603 capabilities of the recipient. 1605 Scanning applications where the data transferred may depend 1606 upon the detailed color image generation capabilities of the 1607 originator. 1609 RFC nnnn Content feature schema for Internet fax 1610 8 January 199 1612 - Examples of typical use: 1614 To describe rendering or scanning capabilities: 1616 (& (CIELAB-L-min>=0) 1617 (CIELAB-L-max<=100) 1618 (CIELAB-a-min>=-75) 1619 (CIELAB-a-max<=+75) 1620 (CIELAB-b-min>=-85) 1621 (CIELAB-b-max<=+85) ) 1623 To describe capabilities required by a document: 1625 (& (CIELAB-L-min=20) 1626 (CIELAB-L-max=80) 1627 (CIELAB-L-min=-35) 1628 (CIELAB-L-max=+55) 1629 (CIELAB-L-min=-45) 1630 (CIELAB-L-max=+65) ) 1632 - Related standards or documents: 1634 CIELAB color space is defined in [19] 1636 CIELAB use for fax is described in ITU T.42 [9] 1638 - Interoperability considerations: 1640 When describing a recipient's capabilities, the minimum and 1641 maximum color component values that can be rendered should be 1642 indicated by inequalities as shown in the examples above. 1644 When describing a document, the actual minimum and maximum 1645 color component values used should be indicated, as shown 1646 above. 1648 - Security considerations: 1650 - Privacy concerns, related to exposure of personal information: 1651 Where feature matching is used to select content applicable 1652 to the physical abilities of a user, unusual values for this 1653 feature tag might give an indication of a user's restricted 1654 abilities. 1656 - Related feature tags: 1658 color [3] 1659 color-space [this document] 1661 RFC nnnn Content feature schema for Internet fax 1662 8 January 199 1664 - Related media types or data formats: 1666 TIFF-FX [7] 1668 - Intended usage: 1670 Internet fax 1671 Color image scanning/rendering applications 1673 - Author/Change controller: 1675 IETF 1677 RFC nnnn Content feature schema for Internet fax 1678 8 January 199 1680 A.7 Image file structure 1682 - Media Feature tag name(s): 1684 image-file-structure 1686 - ASN.1 identifier associated with this feature tag: 1688 [[[New assignments by IANA]]] 1690 - Summary of the media features indicated: 1692 This feature indicates a file structure used for transfer and 1693 presentation of image data. 1695 It does not indicate image data coding: that is described by 1696 separate feature tags (image-coding, etc.). 1698 - Values appropriate for use with this feature tag: 1700 Token 1702 TIFF-FX profiles TIFF-S 1703 [7]: TIFF-F 1704 TIFF-J 1705 TIFF-C 1706 TIFF-L 1707 TIFF-M 1709 (may be extended by further registrations, 1710 to cover non-TIFF image file structures) 1712 - The feature tag is intended primarily for use in the following 1713 applications, protocols, services, or negotiation mechanisms: 1715 Internet fax, and other print or display applications that 1716 transfer image data. 1718 - Examples of typical use: 1720 See Appendix B of this memo. 1722 RFC nnnn Content feature schema for Internet fax 1723 8 January 199 1725 - Considerations particular to use in individual applications, 1726 protocols, services, or negotiation mechanisms: 1728 This tag is intended to provide information about an image 1729 file structure. Information about image data coding is 1730 provided by other tags. 1732 In the case of TIFF-FX image data, there are a number of image 1733 file format constraints that are imposed by the various usage 1734 profiles defined in RFC 2301 [7]. The purpose of the 'image- 1735 file-structure' feature tag is to capture those file format 1736 constraints. 1738 Registration of additional image file structure tags should 1739 focus similarly on image file structure issues, not raw image 1740 data compression and coding. As a guide, an image file 1741 structure may contain image data coded in a variety of ways, 1742 and carries information to describe that coding separately 1743 from MIME content-type labelling, etc. 1745 - Related feature tags: 1747 image-coding [this document] 1749 - Related media types or data formats: 1751 TIFF-FX [7] 1752 TIFF V6.0 (Adobe) [20] 1754 - Intended usage: 1756 Internet fax 1757 Image scanning/rendering applications 1759 - Author/Change controller: 1761 IETF 1763 RFC nnnn Content feature schema for Internet fax 1764 8 January 199 1766 A.8 Image data coding 1768 - Media Feature tag name(s): 1770 image-coding 1772 - ASN.1 identifier associated with this feature tag: 1774 [[[New assignments by IANA]]] 1776 - Summary of the media features indicated: 1778 This feature tag indicates a form of image data compression 1779 and coding used. 1781 It identifies a generic image coding technique used, without 1782 regard to any specific profiling of that technique that may be 1783 applied. Values for this feature are generally applicable 1784 across a wide range of image transfer applications. 1786 This information is distinct from the image file structure and 1787 MRC information conveyed by the 'image-file-structure' tags. 1789 - Values appropriate for use with this feature tag: 1791 Token MH 1792 MR 1793 MMR 1794 JBIG 1795 JPEG 1797 (may be extended by further registrations) 1799 - The feature tag is intended primarily for use in the following 1800 applications, protocols, services, or negotiation mechanisms: 1802 Internet fax, and other applications that transfer image data. 1804 - Examples of typical use: 1806 See Appendix B of this memo. 1808 RFC nnnn Content feature schema for Internet fax 1809 8 January 199 1811 - Related standards or documents: 1813 MH, MR: ITU T.4 [13] 1814 MMR: ITU T.6 [14] 1815 JPEG: ITU T.81 [16] 1816 JBIG: ITU T.82 [17] 1818 - Interoperability considerations: 1820 To establish the correct conditions for interoperability 1821 between systems, capabilities to handle the generic image 1822 coding technique and the specific image coding constraints 1823 must be established. 1825 - Related feature tags: 1827 image-coding-constraint [this document] 1828 JBIG-stripe-size [this document] 1829 image-interleave [this document] 1831 - Related media types or data formats: 1833 TIFF-FX [7] 1835 - Intended usage: 1837 Internet fax 1838 Image scanning/rendering applications 1840 - Author/Change controller: 1842 IETF 1844 RFC nnnn Content feature schema for Internet fax 1845 8 January 199 1847 A.9 Image coding constraint 1849 - Media Feature tag name(s): 1851 image-coding-constraint 1853 - ASN.1 identifier associated with these feature tags: 1855 [[[New assignments by IANA]]] 1857 - Summary of the media features indicated: 1859 This feature tag qualifies the 'image-coding' feature with a 1860 specific profile or usage constraints. 1862 Values for this feature are generally specific to some given 1863 value of 'image-coding' and also to some restricted 1864 application or class of applications. 1866 - Values appropriate for use with this feature tag: 1868 Token JBIG-T85 (bi-level, per ITU T.85) 1869 JBIG-T43 (multi-level, per ITU T.43) 1870 JPEG-T4E (per ITU T.4, Annex E) 1872 (may be extended by further registrations) 1874 - The feature tag is intended primarily for use in the following 1875 applications, protocols, services, or negotiation mechanisms: 1877 Internet fax, and other applications that transfer image data. 1879 The specific values for this feature indicated above are 1880 intended for use with Internet fax. 1882 - Examples of typical use: 1884 See Appendix B of this memo. 1886 - Related standards or documents: 1888 JBIG-T85: ITU T.85 [18] 1889 JBIG-T43: ITU T.43 [10] 1890 JPEG-T4E: ITU T.4 Annex E [13] 1892 RFC nnnn Content feature schema for Internet fax 1893 8 January 199 1895 - Interoperability considerations: 1897 To establish the correct conditions for interoperability 1898 between systems, capabilities to handle the generic image 1899 coding technique and the specific image coding constraints 1900 must be established. 1902 - Related feature tags: 1904 image-coding [this document] 1905 JBIG-stripe-size [this document] 1906 image-interleave [this document] 1908 - Related media types or data formats: 1910 TIFF-FX [7] 1912 - Intended usage: 1914 Internet fax 1915 Color image scanning/rendering applications 1917 - Author/Change controller: 1919 IETF 1921 RFC nnnn Content feature schema for Internet fax 1922 8 January 199 1924 A.10 JBIG stripe size 1926 - Media Feature tag name(s): 1928 JBIG-stripe-size 1930 - ASN.1 identifier associated with these feature tags: 1932 [[[New assignments by IANA]]] 1934 - Summary of the media features indicated: 1936 This feature is a specific usage constraint that is applied to 1937 JBIG image coding (image-coding=JBIG), and indicates the 1938 allowable size for each stripe of an image, except the last. 1940 A stripe of a JBIG image is a delimited horizontal band of 1941 compressed image data that can be decompressed separately from 1942 the surrounding data. 1944 - Values appropriate for use with this feature tag: 1946 Integer (>0) 1948 - The feature tag is intended primarily for use in the following 1949 applications, protocols, services, or negotiation mechanisms: 1951 Internet fax, and other applications that transfer image data. 1953 - Examples of typical use: 1955 (JBIG-stripe-size=128) 1956 (JBIG-stripe-size>0) 1958 - Related standards or documents: 1960 JBIG: ITU T.82 [17] 1961 JBIG-T85: ITU T.85 [18] 1962 JBIG-T43: ITU T.43 [10] 1964 RFC nnnn Content feature schema for Internet fax 1965 8 January 199 1967 - Considerations particular to use in individual applications, 1968 protocols, services, or negotiation mechanisms: 1970 In the case of Internet fax, the specific constraints allowed 1971 for a receiver are those given as examples above. 1973 Specifying a stripe size that is not limited (JBIG-stripe- 1974 size>0) means that an entire page of image data is encoded as 1975 a single unit. This may place considerable demands on the 1976 memory of a receiving system, as the entire stripe needs to be 1977 buffered in memory. 1979 - Interoperability considerations: 1981 To establish the correct conditions for interoperability 1982 between systems, capabilities to handle the generic image 1983 coding technique and the specific image coding constraints 1984 must be established. 1986 - Related feature tags: 1988 image-coding [this document] 1989 image-coding-constraint [this document] 1990 image-interleave [this document] 1992 - Related media types or data formats: 1994 TIFF-FX [7] 1996 - Intended usage: 1998 Internet fax 1999 Color image scanning/rendering applications 2001 - Author/Change controller: 2003 IETF 2005 RFC nnnn Content feature schema for Internet fax 2006 8 January 199 2008 A.11 Image interleave 2010 - Media Feature tag name(s): 2012 image-interleave 2014 - ASN.1 identifier associated with this feature tag: 2016 [[[New assignments by IANA]]] 2018 - Summary of the media features indicated: 2020 This feature indicates an image interleave capability. 2022 It may be used with JBIG images (image-coding=JBIG) to 2023 indicate color plane interleaving of either stripes or entire 2024 image planes. 2026 - Values appropriate for use with this feature tag: 2028 Token Stripe 2029 Plane 2031 - The feature tag is intended primarily for use in the following 2032 applications, protocols, services, or negotiation mechanisms: 2034 Internet fax, and other applications that transfer image data. 2036 - Examples of typical use: 2038 (image-interleave=stripe) 2039 (image-interleave=[stripe,plane]) 2041 - Considerations particular to use in individual applications, 2042 protocols, services, or negotiation mechanisms: 2044 Specifying a plane interleave means that an entire page of 2045 image data must be buffered in order to generate render the 2046 image. This may place considerable demands on the memory of a 2047 sending or receiving system. 2049 - Related feature tags: 2051 image-coding [this document] 2052 JBIG-stripe-size [this document] 2054 - Related media types or data formats: 2056 TIFF-FX [7] 2058 RFC nnnn Content feature schema for Internet fax 2059 8 January 199 2061 - Intended usage: 2063 Internet fax 2064 Color image scanning/rendering applications 2066 - Author/Change controller: 2068 IETF 2070 RFC nnnn Content feature schema for Internet fax 2071 8 January 199 2073 A.12 Color subsampling 2075 - Media Feature tag name(s): 2077 color-subsampling 2079 - ASN.1 identifier associated with this feature tag: 2081 [[[New assignments by IANA]]] 2083 - Summary of the media features indicated: 2085 This feature tag indicates whether color information may be 2086 subsampled with respect to luminance data. 2088 It is used with continuous color images (color=full), color 2089 spaces that use separate luminance and color components 2090 (e.g. color-space=LAB), and image file structures that support 2091 color subsampling. 2093 - Values appropriate for use with this feature tag: 2095 String "1:1:1" 2096 This value indicates a full set of color 2097 component samples for each luminance 2098 component sample. 2100 "4:1:1" 2101 This value indicates a set of color samples 2102 for each luminance sample. 2104 (may be extended by further registrations) 2106 - The feature tag is intended primarily for use in the following 2107 applications, protocols, services, or negotiation mechanisms: 2109 Color image printing and display applications where the data 2110 resource used may depend upon color handling capabilities of 2111 the recipient. 2113 Scanning applications where the data transferred may depend 2114 upon the image generation capabilities of the originator. 2116 - Examples of typical use: 2118 (& (color=full) (color-space=[LAB,CIALAB]) 2119 (color-subsampling=["1:1:1","4:1:1"]) ) 2121 RFC nnnn Content feature schema for Internet fax 2122 8 January 199 2124 - Related feature tags: 2126 color [3] 2127 color-space [this document] 2128 image-file-structure [this document] 2130 - Related media types or data formats: 2132 TIFF-FX [7] 2134 - Intended usage: 2136 Internet fax 2137 Color image scanning/rendering applications 2139 - Author/Change controller: 2141 IETF 2143 RFC nnnn Content feature schema for Internet fax 2144 8 January 199 2146 A.13 MRC availability and mode 2148 - Media Feature tag name(s): 2150 MRC-mode 2152 - ASN.1 identifier associated with this feature tag: 2154 [[[New assignments by IANA]]] 2156 - Summary of the media features indicated: 2158 This feature is used to indicate the availability of MRC 2159 (mixed raster content) image format capability, and also the 2160 MRC mode available. A zero value indicates MRC is not 2161 available, a non-zero value (in the range 1..7) indicates the 2162 available MRC mode number. 2164 An MRC formatted document is actually a collection of several 2165 images, each of which is described by a separate feature 2166 collection. An MRC-capable receiver is presumed to be capable 2167 of accepting any combination of contained images that conform 2168 to the MRC construction rules, where each such image matches 2169 the separately declared resolution, color capability, color 2170 model, image coding, and any other capabilities. 2172 NOTE: an MRC formatted document may appear within a 2173 TIFF image file structure. 2175 Within an MRC-formatted document, multi-level coders 2176 are used for foreground and background images (i.e. 2177 odd-numbered layers: 1, 3, 5, etc.) and bi-level coders 2178 are used for mask layers (i.e. even numbered layers 2, 2179 4, 6, etc.). 2181 - Values appropriate for use with this feature tag: 2183 Integer (0..7) 2185 - The feature tag is intended primarily for use in the following 2186 applications, protocols, services, or negotiation mechanisms: 2188 Internet fax, and other applications that transfer image data. 2190 - Examples of typical use: 2192 See Appendix B of this document. 2194 RFC nnnn Content feature schema for Internet fax 2195 8 January 199 2197 - Related standards or documents: 2199 ITU T.44 [15] 2201 - Interoperability considerations: 2203 To establish the correct conditions for interoperability 2204 between systems, capabilities to handle the MRC mode and any 2205 contained image coding techniques must be established. 2207 - Related feature tags: 2209 image-coding [this document] 2210 MRC-max-stripe-size [this document] 2212 - Related media types or data formats: 2214 TIFF-FX [7] 2216 - Intended usage: 2218 Internet fax 2219 Color image scanning/rendering applications 2221 - Author/Change controller: 2223 IETF 2225 RFC nnnn Content feature schema for Internet fax 2226 8 January 199 2228 A.14 MRC maximum stripe size 2230 - Media Feature tag name(s): 2232 MRC-max-stripe-size 2234 - ASN.1 identifier associated with this feature tag: 2236 [[[New assignments by IANA]]] 2238 - Summary of the media features indicated: 2240 This feature may be used with MRC coding (MRC-mode>=1), and 2241 indicates the maximum number of scan lines in each MRC stripe. 2243 The value given indicates an upper bound on the stripe size. 2244 The actual value may vary between stripes, and the actual size 2245 for each stripe is indicated in the image data. 2247 - Values appropriate for use with this feature tag: 2249 Integer (>0) 2251 - The feature tag is intended primarily for use in the following 2252 applications, protocols, services, or negotiation mechanisms: 2254 Internet fax, and other applications that transfer image data. 2256 - Examples of typical use: 2258 (MRC-max-stripe-size=[0..256]) 2259 (MRC-max-stripe-size>=0) 2261 - Considerations particular to use in individual applications, 2262 protocols, services, or negotiation mechanisms: 2264 For Internet fax, the legal constraints for an image receiver 2265 are those given as examples above. 2267 - Related feature tags: 2269 MRC-mode [this document] 2271 - Related media types or data formats: 2273 TIFF-FX [7] 2275 RFC nnnn Content feature schema for Internet fax 2276 8 January 199 2278 - Intended usage: 2280 Internet fax 2281 Color image scanning/rendering applications 2283 - Author/Change controller: 2285 IETF 2287 RFC nnnn Content feature schema for Internet fax 2288 8 January 199 2290 Appendix B: TIFF mode descriptions 2292 This appendix contains descriptions of the TIFF modes defined by 2293 RFC 2301 [7], presented as feature set expressions in the form 2294 defined by "A syntax for describing media feature sets" [2] and 2295 using the feature schema introduced by this document. 2297 These may be taken as illustrations of the feature set combinations 2298 that are required for the corresponding TIFF profiles described by 2299 RFC 2301. 2301 (Tiff-S) :- 2302 (& (image-file-structure=TIFF-S) 2303 (color=Binary) 2304 (image-coding=MH) (MRC-mode=0) ) 2306 (Tiff-F) :- 2307 (& (image-file-structure=TIFF-F) 2308 (color=Binary) 2309 (image-coding=MH) (MRC-mode=0) ) 2311 (TIFF-J) :- 2312 (& (image-file-structure=TIFF-J) 2313 (color=Binary) 2314 (image-coding=JBIG) (MRC-mode=0) ) 2316 (TIFF-C) :- 2317 (& (image-file-structure=TIFF-C) 2318 (color=Grey) 2319 (image-coding=JPEG) (MRC-mode=0) ) 2321 (TIFF-L) :- 2322 (& (image-file-structure=TIFF-L) 2323 (color=Grey) 2324 (image-coding=JBIG) (MRC-mode=0) ) 2326 (TIFF-M) :- 2327 (& (image-file-structure=TIFF-M) 2328 (color=[Binary,Grey]) 2329 (image-coding=[MH,JPEG]) (MRC-mode>=1) ) 2331 The feature sets described above are minimum requirements for the 2332 corresponding TIFF modes. Thus, MR and MMR image coding are not 2333 mandatory with TIFF mode F, and would be indicated by combining the 2334 expression for (TIFF-F) with (image-coding=MR) and/or 2335 (image-coding=MMR). 2337 RFC nnnn Content feature schema for Internet fax 2338 8 January 199 2340 Similarly, limited, mapped or full color are not mandatory with the 2341 grey/color TIFF modes (C, L and M), and would be indicated by 2342 combining the corresponding expression with (color=limited), 2343 (color=mapped) and/or (color=full). 2345 TIFF profile M is a composite structure that can combine image data 2346 coding options from other profiles: the description above 2347 indicates mandatory features; other options may be indicated by 2348 combining TIFF-M with other options (e.g. color= limited, mapped or 2349 full, and image-coding= MR, MMR or JBIG). 2351 Support for multiple TIFF profiles may be indicated by combining 2352 their expressions with the OR operator; e.g. 2354 (| (TIFF-F) (TIFF-S) (TIFF-J) ) 2356 indicates support for all black-and-white modes. 2358 Appendix C: Revision history 2360 00a 28-Sep-1998 Initial draft. 2362 01a 12-Oct-1998 Incorporated review comments. Described feature 2363 tag for differential x/y resolution ratio. Added 2364 some examples. 2366 01b 19-Oct-1998 Updated section 3.6 on image coding. Added 2367 Appendix B containing feature expressions for the 2368 TIFF modes from RFC 2301. 2370 02a 26-Oct-1998 Update examples. Add separate stripe size 2371 features for JBIG and MRC. 2373 02b 30-Oct-1998 Update examples. Add text clarifying the 2374 description of MRC documents (as a set of feature 2375 collections describing multiple contained images). 2376 Add text describing constrains on resolution and 2377 image coding usage within an MRC document. 2379 02c 11-Nov-1998 Add ITU references. Added terminology: 2380 "capability exchange", "capability identification" 2381 and "capability description". Update JBIG and MRC 2382 stripe size tags. Move subsampling to colour 2383 section. Remove preferred-unit tag. Add T.4, 2384 T.6, T.44 and T.81 references. 2386 02d 16-Nov-1998 Update colour handling features, reflecting 2387 proposed changes to the media features memo [3]. 2388 Update the image coding capability framework. 2389 Updated TIFF mode descriptions in Appendix B. 2391 RFC nnnn Content feature schema for Internet fax 2392 8 January 199 2394 03a 17-Nov-1998 Replace use of 'pix-x', 'pix-y' with 'size-x', 2395 'size-y'. Add registrations in Appendix A. 2397 03b 08-Dec-1998 Remove normative language and reference to RFC2119 2398 (normative statements will be in the main fax 2399 protocol draft). Revise structure of colour 2400 features, and removed color-palette feature. 2401 Define colour feature tags specific to CIELAB 2402 model and colour space. 2404 04a 14-Dec-1998 Update examples to reflect revised feature tags. 2405 Revise description of MRC document in section 3.7. 2406 Clarified interpretation of 'color=fixed'. Change 2407 feature value 'color=fixed' to 'color=limited'. 2409 05a 04-Jan-1999 Incorporate WG last-call comments: change 2410 references to MRC-stripe-size to MRC-max-stripe- 2411 size; similarly references to MRC-maximum-stripe- 2412 size. Change "eifax" to "extended Internet fax". 2413 Added guidance note for image coding feature 2414 usage. Added IANA consideration comments to 2415 Appendix A. 2417 05b 08-Jan-1999 Added new section for IANA considerations; 2418 removed references to fax working group from 2419 registration change control sections. Remove JPEG 2420 from TIFF-L auxiliary predicate. Clarify 2421 description of MRC receiver capabilities in 2422 section A.13. Remove 'color=full' from (TIFF-C) 2423 and (TIFF-M) predicates, and add some explanatory 2424 text. Remove 'color=limited' from (TIFF-L) 2425 predicate. 2427 05c 08-Jan-1999 Minor revisions to TIFF profile illustrations and 2428 descripions in Appendix B. Reformatted 2429 description of 'color=limited' in section 3.5 to 2430 clarify that this does not indicate support for 2431 specific named colors.